On Fri, 5 Oct 2012 14:37:01 +0530
Naveen Krishna Ch
<naveenkrishna.ch@xxxxxxxxx> wrote:
> Hello All,
>
> I'm trying to add an ADC driver under IIO/ADC.
> Machine is DT based so, passing the ADC device as tree node and
> consumer devices (thermistors) as child nodes via DT.
>
> I don't find a frame work to parse the child nodes and probe them like
> I2C does using of/of_i2c.c
Here is my take at DT support in IIO, I wanted to submit that later on
after some more test and cleanup but you can see if it help you.
Alban
>From 15decde13239f09101673b08aa0bd7e67e970b3c Mon Sep 17 00:00:00 2001
From: Alban Bedel <alban.bedel@xxxxxxxxxxxxxxxxx>
Date: Thu, 18 Oct 2012 17:07:29 +0200
Subject: [PATCH] IIO: Add basic DT/devm support for in kernel users
Signed-off-by: Alban Bedel <alban.bedel@xxxxxxxxxxxxxxxxx>
---
.../devicetree/bindings/iio/iio-channel.txt | 27 ++++
drivers/iio/inkern.c | 154 ++++++++++++++++++++
include/linux/iio/consumer.h | 63 ++++++++
3 files changed, 244 insertions(+), 0 deletions(-)
create mode 100644 Documentation/devicetree/bindings/iio/iio-channel.txt
diff --git a/Documentation/devicetree/bindings/iio/iio-channel.txt b/Documentation/devicetree/bindings/iio/iio-channel.txt
new file mode 100644
index 0000000..dc894f4
--- /dev/null
+++ b/Documentation/devicetree/bindings/iio/iio-channel.txt
@@ -0,0 +1,27 @@
+Specifying IIO channels for devices
+===================================
+
+1) iio-channels property
+------------------------
+
+Nodes that makes use of IIO channels should specify them using one or more
+properties, each containing a iio-channels-list':
+
+ iio-channel-list ::= <single-iio-channel> [iio-channel-list]
+ single-iio-channel ::= <iio-channel-phandle> <iio-channel-specifier>
+ iio-channel-phandle : phandle to iio-channel controller node
+ iio-channel-specifier : Array of #iio-channel-cells specifying
+ specific IIO channel (controller specific)
+
+GPIO properties should be named "[<name>-]iio-channels". Exact
+meaning of each gpios property must be documented in the device tree
+binding for each device.
+
+2) iio device nodes
+------------------------
+
+Every IIO device must have #iio-channel-cells contain the size of the
+iio-channel-specifier.
+
+Currently #iio-channel-cells will always be 1 but this will most
+propably change in the future.
diff --git a/drivers/iio/inkern.c b/drivers/iio/inkern.c
index 6d5194f..5986ef5 100644
--- a/drivers/iio/inkern.c
+++ b/drivers/iio/inkern.c
@@ -10,6 +10,7 @@
#include <linux/export.h>
#include <linux/slab.h>
#include <linux/mutex.h>
+#include <linux/of.h>
#include <linux/iio/iio.h>
#include "iio_core.h"
@@ -404,3 +405,156 @@ err_unlock:
return ret;
}
EXPORT_SYMBOL_GPL(iio_get_channel_type);
+
+#ifdef CONFIG_OF
+static int of_dev_node_match(struct device *dev, void *data)
+{
+ return dev->parent ? dev->parent->of_node == data : 0;
+}
+
+int __of_get_named_iio_channel(struct iio_channel* channel,
+ struct device_node *np,
+ const char *propname,
+ int index)
+{
+ struct device *dev;
+ struct of_phandle_args ph;
+ struct iio_dev *indio_dev;
+ int ret, channel_id = -1;
+
+ ret = of_parse_phandle_with_args(np, propname, "#iio-channel-cells",
+ index, &ph);
+ if (ret)
+ return ret;
+
+ dev = bus_find_device(&iio_bus_type, NULL, ph.np,
+ of_dev_node_match);
+ if (!dev)
+ return -EPROBE_DEFER;
+
+ if (ph.args_count > 0)
+ channel_id = ph.args[0];
+
+ indio_dev = dev_to_iio_dev(dev);
+ if (channel_id < 0 || channel_id >= indio_dev->num_channels)
+ return -EINVAL;
+
+ iio_device_get(indio_dev);
+ channel->indio_dev = indio_dev;
+ channel->channel = &indio_dev->channels[channel_id];
+
+ return 0;
+}
+
+/**
+ * of_get_iio_channel() - get a iio channel from a device tree property
+ * @np: Device node to get the channel from
+ * @propname: The property to read
+ * @index: Index of the channel
+ */
+struct iio_channel* of_get_named_iio_channel(struct device_node *np,
+ const char *propname,
+ int index)
+{
+ struct iio_channel* channel;
+ int ret;
+
+ channel = kzalloc(sizeof(*channel), GFP_KERNEL);
+ if (!channel)
+ return ERR_PTR(-ENOMEM);
+
+ ret = __of_get_named_iio_channel(channel, np, propname, index);
+ if (ret) {
+ kfree(channel);
+ return ERR_PTR(ret);
+ }
+ return channel;
+}
+
+EXPORT_SYMBOL_GPL(of_get_named_iio_channel);
+
+struct iio_channel* of_get_named_all_iio_channels(struct device_node *np,
+ const char *propname)
+{
+ int ret, i, cnt;
+ struct iio_channel* channels;
+
+ cnt = of_iio_channel_named_count(np, propname);
+ if (cnt == 0)
+ return NULL;
+
+ channels = kzalloc((cnt+1) * sizeof(*channels), GFP_KERNEL);
+ if (!channels)
+ return ERR_PTR(-ENOMEM);
+
+ for (i = 0 ; i < cnt ; i += 1) {
+ ret = __of_get_named_iio_channel(&channels[i],
+ np, propname, i);
+ if (ret)
+ break;
+ }
+
+ if (ret) {
+ for ( ; i >= 0 ; i -= 1)
+ iio_device_put(channels[i].indio_dev);
+ kfree(channels);
+ return ERR_PTR(ret);
+ }
+
+ return channels;
+
+}
+EXPORT_SYMBOL_GPL(of_get_named_all_iio_channels);
+
+unsigned int of_iio_channel_named_count(struct device_node *np,
+ const char *propname)
+{
+ unsigned int cnt = 0;
+
+ do {
+ int ret;
+
+ ret = of_parse_phandle_with_args(np, propname, "#iio-channel-cells",
+ cnt, NULL);
+ /* A hole in the gpios = <> counts anyway. */
+ if (ret < 0 && ret != -EEXIST)
+ break;
+ } while (++cnt);
+
+ return cnt;
+
+}
+EXPORT_SYMBOL_GPL(of_iio_channel_named_count);
+
+struct iio_channel_devres {
+ struct iio_channel* channel;
+};
+
+static void devm_iio_channel_release(struct device *dev, void *res)
+{
+ struct iio_channel_devres *dr = res;
+ iio_channel_release(dr->channel);
+}
+
+struct iio_channel* devm_iio_channel_get(struct device* dev, int index)
+{
+ struct iio_channel_devres *dr;
+ struct iio_channel *channel;
+
+ channel = of_get_iio_channel(dev->of_node, index);
+ if (IS_ERR(channel))
+ return channel;
+
+ dr = devres_alloc(devm_iio_channel_release, sizeof(*dr), GFP_KERNEL);
+ if (!dr) {
+ iio_channel_release(channel);
+ return ERR_PTR(-ENOMEM);
+ }
+
+ dr->channel = channel;
+ devres_add(dev, dr);
+ return dr->channel;
+}
+EXPORT_SYMBOL_GPL(devm_iio_channel_get);
+
+#endif
diff --git a/include/linux/iio/consumer.h b/include/linux/iio/consumer.h
index e4ff665..e2f958a 100644
--- a/include/linux/iio/consumer.h
+++ b/include/linux/iio/consumer.h
@@ -131,4 +131,67 @@ int iio_read_channel_scale(struct iio_channel *chan, int *val,
int iio_convert_raw_to_processed(struct iio_channel *chan, int raw,
int *processed, unsigned int scale);
+#ifdef CONFIG_OF
+struct iio_channel* of_get_named_iio_channel(struct device_node *np,
+ const char *propname,
+ int index);
+
+struct iio_channel* of_get_named_all_iio_channels(struct device_node *np,
+ const char *propname);
+
+unsigned int of_iio_channel_named_count(struct device_node *np,
+ const char *propname);
+
+#else
+struct iio_channel* of_get_named_iio_channel(struct device_node *np,
+ const char *propname,
+ int index)
+{
+ return ERR_PTR(-ENODEV);
+}
+
+struct iio_channel* of_get_named_all_iio_channels(struct device_node *np,
+ const char *propname)
+{
+ return ERR_PTR(-ENODEV);
+}
+
+unsigned int of_iio_channel_named_count(struct device_node *np,
+ const char *propname)
+{
+ return 0;
+}
+#endif
+
+/**
+ * of_get_iio_channel() - get a iio channel from the device tree
+ * @np: Device node to get the channel from
+ * @index: Index of the channel
+ */
+static inline struct iio_channel* of_get_iio_channel(struct device_node *np,
+ int index)
+{
+ return of_get_named_iio_channel(np, "iio-channels", index);
+}
+
+/**
+ * of_get_all_iio_channels() - get a iio channel from the device tree
+ * @np: Device node to get the channel from
+ */
+static inline struct iio_channel* of_get_all_iio_channels(struct device_node *np)
+{
+ return of_get_named_all_iio_channels(np, "iio-channels");
+}
+
+/**
+ * of_get_iio_channel() - get the number of iio channel from the device tree
+ * @np: Device node to get the number of channel from
+ */
+static inline unsigned int of_iio_channel_count(struct device_node *np)
+{
+ return of_iio_channel_named_count(np, "iio-channels");
+}
+
+struct iio_channel* devm_iio_channel_get(struct device* dev, int index);
+
#endif
--
1.7.0.4
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